A number of striking features in high-energy lepton scattering have forced a re-examination of the standard four-quark-parton models: Recent data show (i) at small $x$ in $\mu N\to \mu X$, $\nu W_2$ increases as $Q^2$ increases; for increasing $E$ in $\nu N\to \mu X$, there are rises in (ii) ${〈y〉}^{\overline{\nu }}$ and (iii) $\frac{{\sigma }^{\overline{\nu }}}{{\sigma }^{\nu }}$. We introduce a $W$ dependence to the sea-quark distributions (motivated by the possible existence of multiquark exotic states) and obtain satisfactory fits to the data (i)-(iii).

• Received 1 February 1977

DOI:https://doi.org/10.1103/PhysRevLett.38.1244